Can mass culture of microalgae be used to absorb significant amount of atmospheric CO2?

Question

I'm talking building numerous layers of algae culture. After that the algae can be used as food source or even fuel. Has any country attempted this?

Answer 1

Yes it can, it has already been experimented upon.

Microphytes, but more specifically phytoplankton and algae, abdorb atmospheric CO2 as you mentioned. By far the greatest concentrations of these organisms is in the seas and oceans. They're not readily visible to the naked eye because they're so small but from space can be seen as blue-green blooms within the water.

The nutrient composition of the oceans varies considerably from one part to the next, one idea that has been trialed is to enrich those parts of the oceans currently devoid of certain nutrients and so encourage the growth of phytoplankton. It's usually iron and / or nitorgen that is lacking and by springling iron filings or enriching the water with urea this deficiency can be compensated for. In doing so more phytoplankton produce, they sequester CO2 from the atmosphere through the process of photosynthesis and when they die they sink to the ocean floor taking the trapped carbon with them.

Similar schemes using freshwater algae have been trialed.

Two leading organisations in the development of these techniques are Planktos and CSIRO Marine and Atmospheric Reserach Centre. Much research has been conducted by Professor Ian Jones from an Australia university (can't recall which one) and his ideas formed part of a BBC documentary.

CSIRO - http://www.cmar.csiro.au/microalgae/index.html
Planktos - http://www.planktos.com/
BBC - http://news.bbc.co.uk/1/hi/programmes/6369401.stm
BBC Documentary Video - http://video.google.com/videoplay?docid=286000425078890061

Answer 2

Excellent Answer Trevor, I share Earth First's concerns too. However, it may be a case of the least of severals evils???

As I understand it, waters that do not contain phytoplankton are clear waters, these are very important habitats for corals which require sunlight to produce food themselves.

Clear water would tend not to heat up as fast as turbid water so increasing plankton growth in the seas would probably also increase the temperature of the water which would obviously have the opposite effect of what we are trying to achieve.

The plankton which have subsequently died, although taking Carbon with them, would eventually decompose producing methane which is an even more potent greenhouse gas.

The negative environmental impact could be negated (possibly) by cultivating algae in specially made inland lakes. Where the algae could be harvested. This bi-product could then be dried and used for food additives for example spirulina and cholrella are used in the health food industry. There may be other algae which would thrive in sewage outfall making use of a known pollutant. Spirulina can also be used further into the food chain such as feed for fish farming.

In my opinion if there is absolutely any possibility whatsoever of avoiding using the sea to the grow micro-algae, then we must actively persue these. The sea should be just left alone, without our intervention. The sea is already warming up from the increased temperature causing large areas of corals to become bleached. Historically we have been extremely unsucessful when we interfer with ecosystems.

Answer 3

This has already been done by nature in the oceans, the largest filtration system we have.Also the largest supplier of food for marine life.. which we in turn eat. Type in phytoplankton on the web search.

Answer 4

Theoretically it can, but it would take a massive investment of resources, both economically and environmentaly, to do such a thing.

It may not be wise to attempt such a thing on a grand scale such as that though. Everytime people try and fix environmental problems we seem to make things worse because we do not always anticipate the repercussions of our actions.

Answer 5

Do you have any concept of how large the oceans are?